Once Hadlar, the leader of the demons, was defeated, the monsters under his command were freed and moved to Delmurin Island to live in peace. Dai, the only human amongst them, was raised by the kind-hearted Brass and longed to become a hero. When Hadlar returned and the previous hero, Avan, came to train Dai for the upcoming battle, his dreams finally became a reality. However, Hadlar shocked everyone by becoming a servant to an even more powerful demon lord and attempting to eliminate Avan. Despite Avan's brave efforts to protect his students, he perished while casting a Self-Sacrifice spell against Hadlar. As Dai and his comrade Pop faced certain defeat, a mystical emblem appeared on Dai's forehead, granting him extraordinary abilities to combat the malevolent force. Together, they set out to avenge their mentor and restore harmony to the world.